The present invention relates to liquid degassing apparatus. The object of the present invention is to provide a mechanism which makes it possible to efficiently remove gaseous components contained in various types of liquids.
The present invention provides a degassing technique for producing ultra-pure water and various types of chemical solutions and test solutions, etc., used in the electronics industry and elsewhere.
In cases where the admixture of air and other gases with ultra-pure water and various other types of liquids is undesirable, degassing is necessary. Various degassing mechanisms have been devised for this purpose. For example, (A) mechanisms in which the liquid that is to be treated is introduced to one side of a porous tube or porous film, and degassing is accomplished from the other side of the porous tube or porous film, and (B) mechanisms in which degassing is accomplished by causing ultrasonic waves to act on the liquid that is to be treated, are known.
In mechanisms of the above-mentioned type (A), the area of contact between the liquid and the porous body must be increased in order to increase the degassing efficiency. For this purpose, means such as reduction of tube diameter or lengthening of tubes, or folding of films into pleats, have been adopted. In all of these cases, however, the amount of gas permeation through the porous body itself is much greater than the amount of gas permeation required for degassing, so that the efficiency is greatly influenced by the velocity at which the gas travels (diffuses) from the interior of the liquid to the point of contact with the porous body. In other words, the large amount of air permeation through the porous body itself is not utilized to full advantage.
Furthermore, in mechanisms which accelerate the movement of gases by causing ultrasonic waves to act on the liquid, it is necessary to introduce a substitute gas after degassing in order to prevent reinvasion by gases in the air. Depending on the intended use, this exchange of gases may be effective in the removal of undesirable gases. However, such an exchange of gases is insufficient in almost all cases.
Furthermore, it is also possible to degas a sprayed liquid directly without using porous tubes. In such a case, however, only a water-sealed pump can be used, since the water droplets penetrate into the vacuum pump. The maximum vacuum pressure of such a pump is approximately 200 Torr, which is extremely low compared to the vacuum pressure of an oil-sealed pump. As a result, the degassing efficiency of such a mechanism is unavoidably poor.